July 1, 2015

How to replace an electric water heater thermostat

By Lyle Weischwill
How to replace an electric water heater thermostat

This DIY repair guide explains how to replace the thermostat in an electric water heater. The thermostat turns the heating element on and off to maintain the water temperature. If the thermostat stops working, the element either won't come on at all and the water is cold or the element stays on too long and the water is scalding. Replace a broken thermostat with the manufacturer-approved replacement part.

Follow these steps to replace a thermostat in Kenmore, State, A. O. Smith, Rheem, Whirlpool and Reliance electric water heaters.

Quick links
Tools required
Work gloves
Phillip screwdriver
Slot screwdriver
Needle nose pliers
Repair difficulty
Time required
30 minutes or less
Repair difficulty
Time required
30 minutes or less
How to replace an electric water heater thermostat repair guide video.

How to replace a water heater theromstat video.

Instructions

  1. 01.

    Shut off the electricity

    Switch the two house circuit breakers dedicated for the water heater to OFF.

    Wear work gloves to protect your hands.

    Switch the water heater circuit breakers off.

    Switch the water heater circuit breakers off.

  2. 02.

    Remove the heating element’s access cover

    Remove the heating element’s access cover mounting screw and pull off the cover.

     Fold the insulation back to expose the thermostat.

    Remove the cover screw.

    Remove the cover screw.

    Remove the cover.

    Remove the cover.

    Fold the insulation up.

    Fold the insulation up.

  3. 03.

    Remove the plastic shield

    Lift up the tab located at the top of the plastic shield to release the shield from the thermostat.

     Remove the shield.

    Remove the shield.

    Remove the shield.

  4. 04.

    Remove the thermostat

    Loosen the screws securing the wires to the thermostat. Pull the wires out.

    To release the thermostat, pull the tabs outward at the top of the thermostat bracket.

    Slide the thermostat up and remove it from behind the thermostat bracket.

    Disconnet the wires.

    Disconnet the wires.

    Release the thermostat.

    Release the thermostat.

    Remove the thermostat.

    Remove the thermostat.

  5. 05.

    Install the new thermostat

    Place the new thermostat in the bracket making sure it fits firmly behind the tabs and against the tank.

    Reattach the wires to the new thermostat and tighten firmly.

    Tip: Use the wire diagram located on top of the water heater showing where each wire connects to the thermostat.
    Install the new thermostat.

    Install the new thermostat.

    Attach the thermostat wires.

    Attach the thermostat wires.

  6. 06.

    Reinstall the plastic shield

    Reinstall the plastic shield over the thermostat and heating element.

    Fold the insulation back over the thermostat and heating element.

    Reinstall the thermostat shield.

    Reinstall the thermostat shield.

  7. 07.

    Reinstall the access cover

    Reinstall the heating element cover and screw.

    Reinstall the heating element cover.

    Reinstall the heating element cover.

    Reinstall the screw.

    Reinstall the screw.

  8. 08.

    Restore power

    Flip the house circuit breakers to the ON position.

    Flip the circuit breakers to the On position.

    Flip the circuit breakers to the On position.

Warning: Undertaking repairs or maintenance to appliances or power equipment can be hazardous. Should you choose to undertake repairs or maintenance, you are assuming the risk of injury to your person or property. In an effort to reduce the risk, use the proper tools and safety equipment noted in the applicable guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs or maintenance, however, should only be performed by a qualified technician.

Symptoms common to all water heaters

Choose a symptom to see related water heater repairs.

Main causes: water supply needs chlorine treatment, anode rod too reactive
Main causes: thermostat temperature set too high, thermostats need adjustment, faulty thermostat, shorted heating element
Main causes: thermostats need adjustment, water heater capacity too low, bad heating element, thermostat failure, excessive tank sediment
Main causes: lack of power, no gas supply, thermostat limit switch tripped, bad element, bad thermostat, gas valve failure, bad thermocouple
Main causes: broken heating element, thermostat failure, excessive tank sediment, tank size too small, burner valve assembly failure
Main causes: faulty pressure relief valve, water is overheating
Main causes: loose water pipe fittings, leaky drain valve, bad temperature-pressure relief valve, leaky heating element, cracked tank

Repair guides for electric water heaters

How to replace an electric water heater thermostat

If the water temperature fluctuates or you don't get enough hot water, follow these instructions to replace your water heater's thermostat.

Repair difficulty
Time required
 30 minutes or less
How to replace a water heater temperature and pressure (T&P) relief valve

Replace a broken temperature/pressure (T&P) relief valve on an electric water heater using these instructions.

Repair difficulty
Time required
 30 minutes or less
How to replace an electric water heater heating element

If your water heater runs out of hot water quickly and one of the two heating elements has failed, replace the element following these step-by-step instructions.

Repair difficulty
Time required
 30 minutes or less

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